Configuration of mobility management measurement method

ABSTRACT

A method of a network node of a cellular communication network connectable to one or more wireless communication devices is disclosed. The method comprises (for each of one or more cells of the cellular communication network) transmitting a respective measurement configuration message to at least one of the wireless communication devices, wherein each measurement configuration message comprises an instruction that the wireless communication device should use a particular signal quality measurement method, the particular signal quality measurement method being selected from a group of available signal quality measurement methods comprising a first signal quality measurement method wherein measurements are made based on a first number of symbols and a second signal quality measurement method wherein measurements are made based on a second number of symbols. The method further comprises receiving one or more signal quality measurement reports from respective ones of the wireless communication devices, wherein each signal quality measurement report comprises an indication of a result of signal quality measurements performed by the respective wireless communication device. Corresponding method of a wireless communication device, a computer program product, a network node, a wireless communication device and arrangements for a network node and a wireless communication device, respectively, are also disclosed.

TECHNICAL FIELD

The present invention relates generally to the field of wirelesscommunication in relation to cellular communication systems. Moreparticularly, it relates to mobility management measurements associatedwith wireless communication.

BACKGROUND

Even though closed formulations (e.g. must, shall, is, etc) may be usedin the following disclosure, this is not to be interpreted as essentialfeatures or facts without alternatives. Contrarily, the disclosure is tobe interpreted as a number of examples and embodiments provided forillustrative and non-limiting purposes.

In current 3GPP (Third Generation Partnership Project) discussions,there are two different RSRQ (Reference Signal Receiver Quality)measurement methods, which are expected to be specified in TS 36.214,Release 12 version 12.0.0 (compare with TS36.214, Release 11, sec.5.1.3). The use of this is dependent on specific scenario. For the useof RSRQ in general the UE (User Equipment, a type of wirelesscommunication device) is required to measure RSRQ only in specificsymbols containing CRS (Cell-specific Reference Signal). This is veryrestricted for the UE and also for the network node.

Signal Quality Measurement

A signal quality measurement comprises of both signal strength andinterference components. Typically it is the ratio of signal strengthand interference in linear scale and difference between signal strengthand interference in log scale.

In general the quality measurement (Q_(rx)) can be expressed as follows:

$\begin{matrix}{Q_{rx} = \frac{P_{rx}}{I + N_{o}}} & (1)\end{matrix}$

Where, P_(rx) is the received power of pilot or reference signal (i.e.signal strength part), N_(o) is the noise power, and I is theinterference. Depending upon the type of quality measurement thecomponent I can be interference on the pilot or the total interferenceon the entire carrier or simply inter-cell interference plus noise.

The signal strength is typically measured on any kind of referencesignal or pilot signal. The interference may include interference fromone or several sources such as reference signals, control channels, datachannels, noise etc. Examples of reference signals or pilot signals areprimary synchronization signal (PSS), secondary synchronization signal(SSS), cell specific reference signal (CRS), reference signal (RS),channel state information reference signal (CSI-RS), positioningreference signal (PRS), demodulation reference signal (DM-RS),multimedia broadcast multicast service reference signal (MBMS RS), etc.Examples of signal quality are signal-to-noise ratio (SNR),signal-to-interference-and-noise ratio (SINR), reference signal receivedquality (RSRQ), common pilot channel energy per chip to noise powerspectral density (CPICH Ec/No), channel state information (CSI), channelquality indication (CQI), channel state information reference signalreceived quality (CSI-RSRQ), etc.

The signal quality measurements (depending e.g. upon the measurement)may be performed on serving cell (or multiple serving cells inmulti-carrier and/or coordinated multipoint (CoMP)) and one or moreneighboring cells. The neighbor cells may belong to serving carrierfrequency or non-serving carrier frequency. The non-serving carrierfrequency can be inter-frequency or inter-RAT (radio access technology)carrier.

Furthermore the quality measurements (depending upon the measurement)may be performed by the UE in high activity RRC (radio resource control)state (e.g. RRC connected state, CELL_DCH state etc) and/or in lowactivity RRC states (e.g. idle state, CELL_PCH state, URA_PCH state,CELL_FACH state etc).

The RSRQ is typically used primarily for mobility in low (e.g. idlestate, idle mode, URA_PCH state, CELL_PCH state etc) and high activityRRC states (e.g. connected state, CELL_FACH state, CELL_DCH state etc)in E-UTRAN and also in other systems for mobility with E-UTRAN.

In high activity state UE is known on cell level by the serving cell andcan be typically scheduled by the serving cell.

Examples of other systems are UTRA FDD/TDD, GERAN/GSM, CDMA2000, HRPD,WLAN etc.

In low activity state the mobility scenario may comprise cell selectionand cell reselection including intra-frequency, inter-frequency andinter-RAT (e.g. between UTRA to LTE (Long Term Evolution) etc). In highactivity state example scenarios are cell change, handover, RRCconnection re-establishment, RRC connection release with direction totarget cell, primary component carrier (PCC) change in CA (carrieraggregation) or PCell (primary cell) change in CA etc.

Quality measurements including RSRQ may typically also be used forvarious applications other than mobility. Other example use cases are:positioning in general, enhanced cell ID (identity) positioning,fingerprinting positioning, minimization of drive tests (MDT), networkplanning, configuration and tuning of radio network parameters,self-organizing network (SON), network monitoring, interferencemanagement, determination and management of load, inter-cellinterference control (ICIC) etc.

In low activity RRC state the UE may typically use quality measurementfor autonomous actions e.g. cell reselection, logging results etc. Inhigh activity RRC state the UE may typically report the measurements(e.g. in a mobility management measurement report) including RSRQ to thenetwork node e.g. eNodeB, RNC (radio network controller), positioningnode etc. The UE may, for example, report the quality measurementperiodically, in an event triggered manner or on event triggeredperiodic manner.

RSRQ

Reference Signal Received Quality (RSRQ) is typically defined as theratio N×RSRP/(E-UTRA carrier RSSI), where N is the number of resourceblocks (RBs) of the E-UTRA carrier RSSI measurement bandwidth. Themeasurements in the numerator and denominator are preferably made overthe same set of resource blocks.

Reference signal received power (RSRP) part of RSRQ is typically definedas the linear average over the power contributions (in [W]) of theresource elements that carry cell-specific reference signals within theconsidered measurement frequency bandwidth.

According to a typical application currently defined, RSSI measurementsmay be performed in two different variants.

According to the first variant (method), E-UTRA (LTE) Carrier ReceivedSignal Strength Indicator (RSSI) in RSRQ comprises the linear average ofthe total received power (in [W]) observed only in OFDM (orthogonalfrequency division multiplex) symbols containing reference symbols forantenna port 0, in the measurement bandwidth, over N number of resourceblocks by the UE from all sources, including co-channel serving andnon-serving cells, adjacent channel interference, thermal noise etc.

According to the second variant (method), if higher-layer signalingindicates certain subframes for performing RSRQ measurements, then RSSIis measured over all OFDM symbols in the indicated subframes. The higherlayer signaling referred to herein may refer to the signaling of one ormore measurement pattern to the UE for RSRQ measurements inheterogeneous network. The heterogeneous network typically comprises lowand high power nodes. According to one example, the serving cell signalsone or more measurement patterns (aka measurement resource restrictionpattern) to inform the UE about the resources or subframes which the UEshould use for performing measurements on a target victim cell (e.g.serving pico cell and/or neighboring pico cells). These resources orsubframes within a measurement pattern where UE should measure RSRQ areprotected from aggressor cell interference. These resources or subframesare also called restricted subframes or protected subframes.

These first and second variants (methods) will also be referred to belowas respectively “old” and “new” mobility management measurementmethods/RSRQ:s/methods/measurements/etc.

In various scenarios, mobility management measurements performedaccording to this approach may not be sufficiently accurate.Particularly, mobility management measurements performed according oneor the other of the first and second methods may not be sufficientlyaccurate.

Therefore, there is a need for alternative approaches to mobilitymanagement measurements. Particularly, there is a need for approaches toselection between the first method and the second method in relation tovarious conditions.

SUMMARY

It should be emphasized that the term “comprises/comprising” when usedin this specification is taken to specify the presence of statedfeatures, integers, steps, or components, but does not preclude thepresence or addition of one or more other features, integers, steps,components, or groups thereof.

The formulation that a network node is connectable to a wirelesscommunication device (or vice versa) is meant to include the case wherethe wireless communication device is in an idle mode.

The formulation that an action takes place for each of one or more cellsof a cellular communication network is meant to include the case whereaction takes place for only one (or some) of the cells of the cellularcommunication network, and not for other cells of the cellularcommunication network. For example, if the cellular communicationnetwork comprises some network nodes with the capability to perform theactions and other network nodes without the capability to perform theactions (e.g. legacy nodes).

It is an object of some embodiments to provide methods and arrangementsfor configuration of mobility management measurements.

Generally mobility management measurements may be seen as a form ofsignal quality measurements, mobility management measurement methods maybe seen as a form of signal quality measurement methods, and mobilitymanagement measurement reports may be seen as a form of signal qualitymeasurement reports.

It can be seen from the RSRQ definition that in the first RSRQdefinition (i.e. RSRQ in general), the RSSI is determined only on OFDMsignals including CRS:s from antenna port 0 while in the second RSRQdefinition (used for heterogeneous network), the RSSI is determinedbased on all OFDM symbols in a sub frame. Hence, the first and secondmeasurement method determines substantially the same measurementquantity (cell load) however, uses different received signals. Inheterogeneous network due to low interference in subframes inmeasurement pattern in which UE has to do the RSRQ measurement, thefirst RSRQ definition will lead to over estimation of RSRQ quality. Dueto this reason in heterogeneous network the RSSI part is measured in allOFDM symbols in the restricted subframe.

According to some embodiments, UE/devices may be allowed to use the oldor new RSRQ definition in order to simplify the UE implementation,network (NW) reporting and RRM (radio resource management). Thissituation will be used as an example throughout this disclosure, butaccording to other embodiments, the old and new RSRQ measurement methodsmay be substituted with any two or more mobility management measurementmethods (e.g. RSRQ measurement methods).

Employing two or more different RSRQ measurement methods may lead todifferent performance (e.g. due to different RSRQ measurement accuracy)depending on the cell load of serving as well as neighboring cells. Aslong as the cells are time aligned and synchronized (i.e. the systemframe numbers (SFN) and OFDM symbols in each sub frame is aligned up toan uncertainty in the order of the cyclic prefix (approx. 4.7 microseconds) and the cell load is moderate or high, there are very smalldifferences (0.5 dB) between the two measurement methods. However, incase of low load and synchronous cells there is a difference that endsup in a bias of the new measurement compared to the old measurementapproach. Furthermore in asynchronous systems, where the neighboringcell timing are different and cells have low load there is a discrepancybetween the measurements. This is especially true for low carrier tointerference ratio, e.g. C/I<0.

FIGS. 1-4 are simulation plots illustrating the cumulative distributionfunction (CDF) of the difference (in dB) between the new RSRQmeasurement method and the old RSRQ measurement method (RSRQ Rel 11) atvarious C/I (−9, −6, −3, 0, 3, 6, 9, 12 and 15 dB) for heavily(P(PDSCH)=100%) and lightly (P(PDSCH)=25%) loaded cells (thus,experienced cell load at a wireless communication device) insynchronized (sync, FIGS. 1 and 2) and asynchronized (async, FIGS. 3 and4) networks (thus, different time synchronization metric values).

The discrepancy between the measurements in certain scenarios may giverise to one or several problems in the prior art Radio resourceManagement (RRM) of the devices in a cell, for instance:

-   -   Each of the methods may have different benefits (pros) and        drawbacks (cons). For some load conditions between the cells,        one of the methods might give a more true value than the other.        However, a typical device does not know which method to use and        when to use it, and hence may end up using a non-optimal RSRQ        measure giving capacity degradation in the system when the NW        node is not provided with (and/or does not use the best RSRQ        measure.    -   The network node may not know which method a device is using for        determining the RSRQ in an approach where devices are allowed to        use any of the methods regardless of radio scenario. Again        non-optimized handover (HO) decision may be made by the RRM in        the NW node.    -   A typical method does not utilize the actual difference in RSRQ        results depending on RSRQ measurement method and hence cannot        utilize this in the cellular NW deployment.

According to some embodiments, the above mentioned short comings of thedifferent RSRQ measurement methods are taken into account and a choiceof (preferably the best) measurement method is made based on currentradio scenario.

Some embodiments concern areas such as RRM, Signal Measurements, RSRQ,LTE, Mobility, and/or Load.

The embodiments are applicable to any signal quality measured by the UEon signals from one or more cells. However for simplicity theembodiments are described for RSRQ measurement.

Some embodiments use an approach to RSRQ measurements where the use ofdifferent RSRQ definitions in a wide range of scenarios is exploited toensure overall benefit especially in mobility performance.

Several aspects, embodiments and examples are disclosed herein. At leastsome embodiments are:

A method of a UE of performing a signal quality measurement, the methodcomprises:

-   -   obtaining information whether to perform the signal quality        measurement based on first or second measurement methods,        wherein the first measurement method using a subset of the        received signal used in the second measurement method;    -   selecting first or second measurement method based on obtained        information; and    -   performing the signal quality measurement using the selected        method.

A method of a NW node serving a UE of configuring the UE to perform asignal quality measurement, the method comprises:

-   -   determining whether the UE should perform the signal quality        measurement based on first or measurement methods, wherein the        first measurement method using a subset of the received signal        used in the second measurement method; and    -   configuring the UE to perform the signal quality measurement        based on the determined method.

The following describes some example aspect and embodiments.

A first aspect is a method of a wireless communication deviceconnectable to a cellular communication network. The method comprises(for each of one or more cells of the cellular communication network)acquiring at least one of an experienced cell load of the cell and atime synchronization metric indicative of a time synchronization betweenthe cell and one or more other cells of the cellular communicationnetwork, selecting a mobility management measurement method based on atleast one of the experienced cell load and the time synchronizationmetric, and performing mobility management measurements according to theselected method.

The method may be suitable for mobility management measurements.

The one or more cells may be one or more detected cells, for example, aserving/camping cell and/or one or more neighboring cells.

Acquiring the experienced load and/or the time synchronization metricmay be performed according to any suitable known or future method. Forexample, the experienced load and/or the time synchronization metric (oran indication thereof) may be received from a network node.Alternatively or additionally, the experienced load and/or the timesynchronization metric may be determined based on measurements and/orcalculations.

The mobility management measurement method may be selected from a groupof available mobility management measurement methods. The group ofavailable mobility management measurement methods may comprise a firstmethod wherein measurements are made based on a first number of symbolsand a second method wherein measurements are made based on a secondnumber of symbols. The second number of symbols may be larger than thefirst number of symbols (or vice versa). The first number of symbols maybe a subset of the second number of symbols (or vice versa).

The mobility management measurement method may comprise radio resourcemanagement (RRM) and/or radio resource control (RRC) measurements. Forexample, the mobility management measurement method may comprise amethod to measure and/or calculate a received signal strength indication(RSSI) value and/or a reference signal received quality (RSRQ) value.

In some embodiments, the method may further comprise transmitting amobility management measurement report to a network node of the cellularcommunication network comprising an indication of a result of theperformed mobility management measurements.

The mobility management measurement report may be indicative of theselected mobility management measurement method, according to someembodiments.

In some embodiments, the method may further comprise performing a cellreselection procedure based on the performed mobility managementmeasurements.

In some embodiments, the method may further comprise receiving ameasurement configuration message from a network node of the cellularcommunication network, and selecting a mobility management measurementmethod may be further based on the measurement configuration message.

The measurement configuration message and/or the mobility managementmeasurement report may be comprised in a RRC configuration message.

The mobility management measurement report may comprise one or more bitsadapted to carry information indicative of the selected mobilitymanagement measurement method.

The measurement configuration message may comprise one or more of:

-   -   an indication regarding the cell load;    -   an indication regarding the time synchronization;    -   an indication of a group of available mobility management        measurement methods (the group may comprise one or more        available methods);    -   a request to receive an indication of the selected mobility        management measurement method in the mobility management        measurement report; and    -   a request for mobility management measurements to be performed        and reported according to more than one selected mobility        management measurement method.

When the configuration explicitly instructs the wireless communicationdevice that it should use one particular mobility management measurementmethod (the group comprises only one available method), the steps ofacquiring and/or selecting may be skipped according to some embodiments.The steps of acquiring and/or selecting may also be skipped according tosome embodiments when the reports are to be used for statisticalpurposes according to some embodiments (see e.g. FIG. 10).

Thus, in some embodiments, the method may comprise (for each of one ormore cells of the cellular communication network) receiving ameasurement configuration message from a network node of the cellularcommunication network, wherein the measurement configuration messagecomprises an instruction that the wireless communication device shoulduse a particular mobility management measurement method, the particularmobility management measurement method selected from a group ofavailable mobility management measurement methods comprising a firstmobility management measurement method wherein measurements are madebased on a first number of symbols and a second mobility managementmeasurement method wherein measurements are made based on a secondnumber of symbols, and performing mobility management measurementsaccording to the particular mobility management measurement method.

In some embodiments, the method may further comprise transmitting amobility management measurement report to the network node of thecellular communication network comprising an indication of a result ofthe performed mobility management measurements.

The first number of symbols may be a subset of the second number ofsymbols.

The second number of symbols may comprise all orthogonal frequencydivision multiplex (OFDM) symbols in a subframe of the received signaland the first number of symbols may comprise only orthogonal frequencydivision multiplex (OFDM) symbols in a subframe of the received signalthat carry cell-specific reference signals (CRS).

The mobility management measurement methods may comprise methods tomeasure a received signal strength indication (RSSI) and calculate areference signal received quality (RSRQ) value based on the measuredreceived signal strength indication.

In some embodiments, the method may further comprise performing theparticular mobility management measurement method in one or more of thefollowing states: Radio Resource Control—RRC—idle state, Radio ResourceControl—RRC—connected state, Idle mode, Universal terrestrial radioaccess network Registration Area Paging Channel (URA_PCH) state, CellPaging Channel (CELL_PCH) state, Forward Access Channel (CELL_FACH)state, and Dedicated Channel (CELL_DCH) state.

In some embodiments, the method may further comprise transmitting acapability indication message to the network node of the cellularcommunication network, wherein the capability indication message isindicative of a collection of mobility management measurement methodssupported by the wireless communication device. The collection maycomprise the first and second mobility management measurement methods.

According to some embodiments, a method is provided of a wirelesscommunication device connectable to a cellular communication network.

The method may comprise (for each of one or more cells of the cellularcommunication network) selecting a signal quality measurement methodfrom a group of available signal quality measurement methods comprisinga first signal quality measurement method wherein measurements are madebased on a first number of symbols and a second signal qualitymeasurement method wherein measurements are made based on a secondnumber of symbols, and performing signal quality measurements accordingto the selected method.

A second aspect is a method of a network node of a cellularcommunication network connectable to one or more wireless communicationdevices.

The method comprises (for each of one or more cells of the cellularcommunication network) acquiring at least one of an experienced cellload of the cell and a time synchronization metric indicative of a timesynchronization between the cell and one or more other cells of thecellular communication network, receiving one or more mobilitymanagement measurement reports from respective wireless communicationdevices, wherein each mobility management measurement report comprisesan indication of a result of mobility management measurements performedby the respective wireless communication device, and compensating atleast one of the result indications based on at least one of theexperienced cell load and the time synchronization metric.

The method may be suitable for mobility management.

In some embodiments, the method may further comprise using thecompensated result indication in a mobility management procedure.

In some embodiments, the method may further comprise using thecompensated result indication for statistical purposes.

The one or more cells may, for example, be a cell served by the networknode and/or one or more neighboring cells.

Acquiring the experienced load and/or the time synchronization metricmay be performed according to any suitable known or future method. Forexample, the experienced load and/or the time synchronization metric (oran indication thereof) may be received from other network nodes of thecellular communication network and/or from one or more wirelesscommunication devices. Alternatively or additionally, the experiencedload and/or the time synchronization metric may be determined based onmeasurements and/or calculations.

The mobility management measurements may comprise radio resourcemanagement (RRM) and/or radio resource control (RRC) measurements. Forexample, the mobility management measurements may comprise a receivedsignal strength indication (RSSI) value and/or a reference signalreceived quality (RSRQ) value.

Compensating a result indication (e.g. a mobility management measurementvalue) may comprise scaling and/or biasing the result indication.

For example, the result indication may be biased in relation to anexperienced load. If, for example, an experienced load is lower than aload threshold, a bias value may be added (or subtracted) from theresult indication. In some embodiments, several threshold andcorresponding bias values may be applied.

Alternatively or additionally, the result indication may be scaled inrelation to a time synchronization metric. For example, measurements ofan asynchronous situation and affected by high interference may be givena lower weight.

The mobility management measurement report may be indicative of amobility management measurement method selected by the respectivewireless communication device according to some embodiments.

Compensating the result indication may be further based on the selectedmobility management measurement method. For example, result indicationbased on a selected first method may be left unchanged while a resultindication based on a selected second method may be compensated.

In some embodiments, the method may further comprise transmitting arespective measurement configuration message to at least one of therespective wireless communication devices.

The respective measurement configuration message(s) may be transmittedprior to receiving the one or more mobility management measurementreports.

The measurement configuration message and/or the mobility managementmeasurement report may be comprised in a RRC configuration message.

The measurement configuration message may comprise one or more of:

-   -   an indication regarding the cell load;    -   an indication regarding the time synchronization;    -   an indication of a group of available mobility management        measurement methods (the group may comprise one or more        available methods);    -   a request to receive an indication of the selected mobility        management measurement method in the mobility management        measurement report; and    -   a request for mobility management measurements to be performed        and reported according to more than one selected mobility        management measurement method.

When the configuration explicitly instructs the wireless communicationdevice that it should use one particular mobility management measurementmethod (the group comprises only one available method), the step ofcompensating may be skipped according to some embodiments (see e.g. FIG.8). The step of compensating may also be skipped according to someembodiments when the reports are to be used for statistical purposesaccording to some embodiments (see e.g. FIG. 9). In the latter case, theacquiring step may also be skipped according to some embodiments.

Thus, in some embodiments, the method may comprise (for each of one ormore cells of the cellular communication network) transmitting arespective measurement configuration message to at least one of thewireless communication devices, wherein each measurement configurationmessage comprises an instruction that the wireless communication deviceshould use a particular mobility management measurement method, theparticular mobility management measurement method being selected from agroup of available mobility management measurement methods comprising afirst mobility management measurement method wherein measurements aremade based on a first number of symbols and a second mobility managementmeasurement method wherein measurements are made based on a secondnumber of symbols, and receiving one or more mobility managementmeasurement reports from respective ones of the wireless communicationdevices, wherein each mobility management measurement report comprisesan indication of a result of mobility management measurements performedby the respective wireless communication device.

The first number of symbols may be a subset of the second number ofsymbols.

The second number of symbols may comprise all orthogonal frequencydivision multiplex (OFDM) symbols in a subframe of the received signaland the first number of symbols may comprise only orthogonal frequencydivision multiplex (OFDM) symbols in a subframe of the received signalthat carry cell-specific reference signals (CRS).

In some embodiments, the method may further comprise acquiring at leastone of an experienced cell load of the cell and a time synchronizationmetric indicative of a time synchronization between the cell and one ormore other cells of the cellular communication network. The particularmobility management measurement method may be selected based on one ormore of the experienced cell load and the time synchronization metric.

The mobility management measurement methods may comprise methods tomeasure a received signal strength indication (RSSI) and calculate areference signal received quality (RSRQ) value based on the measuredreceived signal strength indication.

In some embodiments, the particular mobility management measurementmethod is to be performed by the respective wireless communicationdevice in one or more of the following states: Radio ResourceControl—RRC—idle state, Radio Resource Control—RRC—connected state, Idlemode, Universal terrestrial radio access network Registration AreaPaging Channel (URA_PCH) state, Cell Paging Channel (CELL_PCH) state,Forward Access Channel (CELL_FACH) state, and Dedicated Channel(CELL_DCH) state.

The method may further comprise using the result of mobility managementmeasurements in a mobility management procedure.

According to some embodiments, the method may further comprise receivinga capability indication message from at least one of the respectivewireless communication devices, wherein the capability indicationmessage is indicative of a collection of mobility management measurementmethods supported by the respective wireless communication device.

The capability indication message may typically be received prior toreceiving the one or more mobility management measurement reports andpossible transmission of respective measurement configuration message(s)may be performed in response to receiving the capability indicationmessage. The respective measurement configuration message(s) may bebased on the capability indication message.

A third aspect is a computer program product comprising a computerreadable medium, having thereon a computer program comprising programinstructions. The computer program is loadable into a data-processingunit and adapted to cause the data-processing unit to execute methodsteps according to any of the first and second aspects when the computerprogram is run by the data-processing unit.

A fourth aspect is an arrangement of a wireless communication deviceconnectable to a cellular communication network.

The arrangement comprises a selector, a mobility management measurementunit and at least one of a cell load acquiring unit and a timesynchronization metric acquiring unit, wherein (for each of one or morecells of the cellular communication network) the cell load acquiringunit is adapted to acquiring an experienced cell load of the cell, thetime synchronization metric acquiring unit is adapted to acquire a timesynchronization metric indicative of a time synchronization between thecell and one or more other cells of the cellular communication network,the selector is adapted to select a mobility management measurementmethod based on at least one of the experienced cell load and the timesynchronization metric, and the mobility management measurement unit isadapted to perform mobility management measurements according to theselected method.

The arrangement may be suitable for mobility management measurements.

The one or more cells may be one or more detected cells, for example, aserving/camping cell and/or one or more neighboring cells.

Acquiring the experienced load and/or the time synchronization metricmay be performed according to any suitable known or future method. Forexample, the arrangement may comprise a receiver adapted to receive theexperienced load and/or the time synchronization metric (or anindication thereof) from a network node. Alternatively or additionally,the experienced load and/or the time synchronization metric may bedetermined based on measurements and/or calculations.

The selector may be adapted to select the mobility managementmeasurement method from a group of available mobility managementmeasurement methods. The group of available mobility managementmeasurement methods may comprise a first method wherein measurements aremade based on a first number of symbols and a second method whereinmeasurements are made based on a second number of symbols. The firstnumber of symbols may be larger than the second number of symbols. Thesecond number of symbols may be a subset of the first number of symbols.

The mobility management measurement method may comprise radio resourcemanagement (RRM) and/or radio resource control (RRC) measurements. Forexample, the mobility management measurement method may comprise amethod to measure and/or calculate a received signal strength indication(RSSI) value and/or a reference signal received quality (RSRQ) value.

In some embodiments, the arrangement may further comprise a transmitteradapted to transmit a mobility management measurement report to anetwork node of the cellular communication network comprising anindication of a result of the performed mobility managementmeasurements.

The mobility management measurement report may be indicative of theselected mobility management measurement method.

In some embodiments, the arrangement may further comprise a cellselection unit adapted to perform a cell reselection procedure based onthe mobility management measurements.

In some embodiments, the arrangement may further comprise a receiveradapted to receive a measurement configuration message from a networknode of the cellular communication network, and the selector may beadapted to select the mobility management measurement method furtherbased on the measurement configuration message.

The measurement configuration message and/or the mobility managementmeasurement report may be comprised in a RRC configuration message.

The mobility management measurement report may comprise one or more bitsadapted to carry information indicative of the selected mobilitymanagement measurement method.

The measurement configuration message may comprise one or more of:

-   -   an indication regarding the cell load;    -   an indication regarding the time synchronization;    -   an indication of a group of available mobility management        measurement methods (the group may comprise one or more        available methods);    -   a request to receive an indication of the selected mobility        management measurement method in the mobility management        measurement report; and    -   a request for mobility management measurements to be performed        and reported according to more than one selected mobility        management measurement method.

In some embodiments, the arrangement may further comprise a transmitteradapted to transmit a capability indication message to a network node ofthe cellular communication network, and the capability indicationmessage may be indicative of a collection of mobility managementmeasurement methods supported by the wireless communication device.

In some embodiments, the selector may be excluded from the arrangement(compare with corresponding embodiments of the first aspect).

Thus, in some embodiments, the arrangement comprises a mobilitymanagement measurement unit and a receiver, wherein (for each of one ormore cells of the cellular communication network) the receiver isadapted to receive a measurement configuration message from a networknode of the cellular communication network, wherein the measurementconfiguration message comprises an instruction that the wirelesscommunication device should use a particular mobility managementmeasurement method, the particular mobility management measurementmethod selected from a group of available mobility managementmeasurement methods comprising a first mobility management measurementmethod wherein measurements are made based on a first number of symbolsand a second mobility management measurement method wherein measurementsare made based on a second number of symbols, and the mobilitymanagement measurement unit is adapted to perform mobility managementmeasurements according to the particular mobility management measurementmethod.

In some embodiments, the arrangement may further comprise a transmitteradapted to transmit a mobility management measurement report to thenetwork node of the cellular communication network comprising anindication of a result of the performed mobility managementmeasurements.

A fifth aspect is a network node for a cellular communication networkcomprising the arrangement of the fourth aspect.

A sixth aspect is a mobility management arrangement of a network node ofa cellular communication network connectable to one or more wirelesscommunication devices.

The arrangement comprises a receiver, a compensator and at least one ofa cell load acquiring unit and a time synchronization metric acquiringunit, wherein (for each of one or more cells of the cellularcommunication network) the cell load acquiring unit is adapted toacquiring an experienced cell load of the cell, the time synchronizationmetric acquiring unit is adapted to acquire a time synchronizationmetric indicative of a time synchronization between the cell and one ormore other cells of the cellular communication network, the receiver isadapted to receive one or more mobility management measurement reportsfrom respective wireless communication devices, wherein each mobilitymanagement measurement report comprises an indication of a result ofmobility management measurements performed by the respective wirelesscommunication device, and the compensator is adapted to compensate atleast one of the result indications based on at least one of theexperienced cell load and the time synchronization metric.

The arrangement may be suitable for mobility management.

In some embodiments, the arrangement may further comprise a mobilitymanagement unit adapted to use the compensated result indication in amobility management procedure.

In some embodiments, the arrangement may further comprise a statisticalunit adapted to use the compensated result indication for statisticalpurposes.

The one or more cells may, for example, be a cell served by the networknode and/or one or more neighboring cells.

Acquiring the experienced load and/or the time synchronization metricmay be performed according to any suitable known or future method. Forexample, the arrangement may comprise a receiver adapted to receive theexperienced load and/or the time synchronization metric (or anindication thereof) from other network nodes of the cellularcommunication network and/or from one or more wireless communicationdevices. Alternatively or additionally, the experienced load and/or thetime synchronization metric may be determined based on measurementsand/or calculations.

The mobility management measurements may comprise radio resourcemanagement (RRM) and/or radio resource control (RRC) measurements. Forexample, the mobility management measurements may comprise a receivedsignal strength indication (RSSI) value and/or a reference signalreceived quality (RSRQ) value.

Compensating a result indication (e.g. a mobility management measurementvalue) may comprise scaling and/or biasing the result indication.

For example, the result indication may be biased in relation to anexperienced load. If, for example, an experienced load is lower than aload threshold, a bias value may be added (or subtracted) from theresult indication. In some embodiments, several threshold andcorresponding bias values may be applied.

Alternatively or additionally, the result indication may be scaled inrelation to a time synchronization metric. For example, measurements ofan asynchronous situation and affected by high interference may be givena lower weight.

The mobility management measurement report may be indicative of amobility management measurement method selected by the respectivewireless communication device.

Compensating the result indication may be further based on the selectedmobility management measurement method. For example, result indicationbased on a selected first method may be left unchanged while a resultindication based on a selected second method may be compensated.

In some embodiments, the arrangement may further comprise a transmitteradapted to transmit a respective measurement configuration message to atleast one of the respective wireless communication devices.

The respective measurement configuration message(s) may be transmittedprior to receiving the one or more mobility management measurementreports.

The measurement configuration message and/or the mobility managementmeasurement report may be comprised in a RRC configuration message.

The measurement configuration message may comprise one or more of:

-   -   an indication regarding the cell load;    -   an indication regarding the time synchronization;    -   an indication of a group of available mobility management        measurement methods (the group may comprise one or more        available methods);    -   a request to receive an indication of the selected mobility        management measurement method in the mobility management        measurement report; and    -   a request for mobility management measurements to be performed        and reported according to more than one selected mobility        management measurement method.

In some embodiments, the compensator may be excluded from thearrangement (compare with corresponding embodiments of the secondaspect).

Thus, in some embodiments, the arrangement comprises a receiver and atransmitter, wherein (for each of one or more cells of the cellularcommunication network) the transmitter is adapted to transmit arespective measurement configuration message to at least one of thewireless communication devices, wherein each measurement configurationmessage comprises an instruction that the wireless communication deviceshould use a particular mobility management measurement method, theparticular mobility management measurement method being selected from agroup of available mobility management measurement methods comprising afirst mobility management measurement method wherein measurements aremade based on a first number of symbols and a second mobility managementmeasurement method wherein measurements are made based on a secondnumber of symbols, and the receiver is adapted to receive one or moremobility management measurement reports from respective ones of thewireless communication devices, wherein each mobility managementmeasurement report comprises an indication of a result of mobilitymanagement measurements performed by the respective wirelesscommunication device.

In some embodiments, the arrangement may further comprise a receiveradapted to receive a capability indication message from at least one ofthe respective wireless communication devices, wherein the capabilityindication message may be indicative of a collection of mobilitymanagement measurement methods supported by the respective wirelesscommunication device.

The capability indication message may typically be received prior toreceiving the one or more mobility management measurement reports andpossible transmission of respective measurement configuration message(s)may be performed in response to receiving the capability indicationmessage. The respective measurement configuration message(s) may bebased on the capability indication message.

A seventh aspect is a network node for a cellular communication networkcomprising the arrangement of the sixth aspect.

In some embodiments, the various methods, arrangements and devicesexemplified above according to the various aspects and embodiments mayadditionally have features identical with or corresponding to any of thevarious features as explained for other of the various methods,arrangements and devices according to the various aspects andembodiments. For example, an arrangement may have features identicalwith or corresponding to any of the various features as explained for acorresponding method, and vice versa.

In the examples above, a cellular communication network has been usedfor illustrative purposes. Generally, embodiments may be equallyapplicable in any suitable wireless communication system, for example, awireless local area network (WLAN) system.

Correspondingly, the wireless communication device and the network nodeused in the examples above for illustrative purposes may, according tosome embodiments, be substituted by any suitable wireless communicationnodes.

In embodiments, where the wireless communication system is not acellular communication system, “cell” as used in the examples above maybe substituted by another suitable concept, for example, a coverage areaof a wireless communication node (e.g. a WLAN access point).

In some embodiments other parameters than the experienced cell loadand/or the time synchronization metric may be applied in a similarmanner. For example, a signal quality metric (e.g. C/I, SNR, SINR,Es/Iot (symbol energy to interference over thermal noise), etc.) may beused instead of (or in addition to) the cell load in the examples above.

An advantage of some embodiments is that an approach to select betweenthe first and second mobility management measurement methods isprovided. Another advantage of some embodiments is that an approach toconfiguring wireless communication devices for mobility managementmeasurements is provided.

Yet another advantage of some embodiments is that mobility managementmeasurements may be adapted by selection between the first and secondmobility management measurement method based on the cell load and/or theinterference conditions.

Yet another advantage of some embodiments is that mobility managementmeasurements may be adapted by selection between the first and secondmobility management measurement method based on the deployment scenarioand/or based on the power class of base stations for which themeasurements are to be performed.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objects, features and advantages will appear from the followingdetailed description of embodiments, with reference being made to theaccompanying drawings, in which:

FIGS. 1-4 are simulation plots illustrating differences in the resultusing the first and second mobility management measurement method;

FIGS. 5-10 are flowcharts illustrating example method steps according tosome embodiments;

FIG. 11 is a combined flowchart and signaling diagram illustratingexample method steps and example signals according to some embodiments;

FIGS. 12-13 are block diagrams illustrating example arrangementsaccording to some embodiments;

FIG. 14 is a schematic drawing illustrating a computer readable mediumaccording to some embodiments; and

FIG. 15 is a block diagram illustrating an example arrangement accordingto some embodiments.

DETAILED DESCRIPTION

In the following, embodiments will be described where a mobilitymanagement measurement method is selected (e.g. a choice of signalquality measurement method may be provided). In some embodiments, one ormore wireless communication devices are configured by a network node toapply the selected mobility management measurement method.

In the description below we may use the term UE or device or wirelessdevice. However it may also be a sensor, modem, target device, device todevice UE, machine type UE or UE capable of machine to machinecommunication, a sensor equipped with UE PDA (personal digitalequipment), iPAD, Tablet, mobile terminals, smart phone, laptop embeddedequipped (LEE), laptop mounted equipment (LME), USB dongles, CustomerPremises Equipment (CPE) etc.

Also in the embodiments a general terminology, “radio network node” orsimply “network node (NW node)”, is used and it refers to any kind ofnetwork node which may comprise of base station, radio base station,base transceiver station, base station controller, network controller,evolved Node B (eNB), Node B, relay node, positioning node, E-SMLC(evolved serving mobile location center), location server, repeater,access point, radio access point, Remote Radio Unit (RRU) Remote RadioHead (RRH), multi-standard radio (MSR) radio node such as MSR BS(multi-standard radio base station) nodes in distributed antenna system(DAS), SON node, O&M (operations and maintenance), OSS (operation systemsupport), MDT (minimization of drive test) node, Core network node, MME(mobility management entity), etc.

Furthermore, below is exemplified with an LTE system and signalmeasurement method may be RSRQ, however the invention may not be limitedto that case but also apply to other kinds of quality measurementsand/or cellular communication systems.

Hence, some embodiments refer to a first and second (mobilitymanagement) measurement method measuring substantially the samemeasurement quantity, but using different received signals for obtainingthe first and second signal measurement (or the first measurement methodusing a subset of the received signal used in the second measurementmethod) and method and apparatus for a control unit controlling which offirst or second measurement method to be used for measuring themeasurement quantity for a certain cell. Some embodiments also refer toa first and second measurement method measuring substantially the samemeasurement quantity, but using different received signals for obtaininga part of the first and second signal measurement (or the firstmeasurement method using a subset of the received signal used in thesecond measurement method) and method and apparatus for a control unitcontrolling which of first or second measurement method to be used formeasuring the measurement quantity for a certain cell. The part hereincan be the numerator or denominator in the measurement quality. Forexample it may be only the RSSI part of the RSRQ, whereas RSRP ismeasured over the same reference signals in both first and secondmeasurement methods. As an example in the first measurement method UEuses only CRS symbols (i.e. OFDM symbols containing CRS) for measuringRSSI for RSRQ whereas in the second measurement method the UE uses allsymbols in a subframe for measuring RSSI for RSRQ. In yet anotherexample in the first measurement method UE uses only CRS symbols (i.e.OFDM symbols containing CRS) for measuring RSSI for RSRQ whereas in thesecond measurement method the UE uses any set of symbols (i.e. can beless than all available symbols) in a subframe for measuring RSSI forRSRQ. The control unit may be in either the device or in the NW node, orparts of the control unit may be in device and other parts in the NWnode.

The invention covers several embodiments, and a number of example groupsof embodiments (each group denoted as A, B, C, D, E, F respectively)will be described in detail below.

UE Based Decision for Switch of RSRQ Measurement Method (A)

This is purely UE based implementation embodiment for switching betweenfirst and second types of RSRQ measurement method. In this embodiment itis assumed that the UE is allowed to use old and new RSRQ (i.e. firstand second measurement methods) and switch between methods based oninternal measurements. It may therefore be pre-defined (e.g. specifiedin the standard) that the UE is allowed to use first or secondmeasurement method for RSRQ measurements. Both first and second methodswill also be pre-defined. Then the UE switches between using the old andnew RSRQ definitions based on one or more criteria related to the radiocharacteristics. Examples of criteria are at least one of (experienced)cell load, synchronization status of cells in network (timesynchronization metric) as it knows from the cell timing determined fromthe cells search. Yet another criterion could be the radio environmentwhere the UE is operating e.g. AWGN (additive white Gaussian noise),user speed, delay spread of the radio channel, rural environment, highspeed etc. The UE may also contain stored information about the celltiming e.g. based on historical date or cell search carried out in thepast. The UE may also obtain information about the synchronizationstatus of the cells from the network node. The synchronization status ofcertain cells or parts of network may also be pre-defined e.g. it may bepre-defined that cells used in CoMP or in multi-carrier or carrieraggregation operation are synchronized. The cell timing herein refers tothe transmit timing of a signal transmitted by the cell as observed orobtained by the UE. Based on the cell timing, the device may determinewhether cells are time aligned and synchronized or not. The time alignedand synchronized cells mean that their frame transmit timing are withincertain accuracy e.g. within +/−3 μs (or within the cyclic prefix). Inone example embodiment, in case cells are synchronized the new RSRQdefinition may be used. In case of asynchronous cells detected, the oldRSRQ may be used. In yet another embodiment also estimated cell load maybe used. Cell load may be determined by the RSRQ measurement itselfand/or other measurements like CQI, indicating high (say >65% ofPDSCH—physical downlink shared channel) RBs allocated, medium (30-65%)or low load (<.30%). The UE may also determine cell load by reading thescheduling information sent on downlink (DL) control channel e.g. PDCCH(physical downlink control channel) in serving and neighboring cells.The UE when operating in CoMP scenario can read control channels ofplurality of nodes or cells. Hence, in case of asynchronous but highload in most of the cells (or at least in the serving cell), new RSRQmeasurement method is used, while in case of low or medium load in atleast one cell (may be serving or neighboring cell) the old RSRQmeasurement is used. The RSRQ measurement method may be chosenindependently for each detected cell, or may be the same for alldetected cells. Furthermore, the RSRQ method may be different fordifferent carrier frequencies as well.

In some embodiments, the UE may be restricted with regard to switchingbetween different RSRQ measurement methods. For example, it may not beallowed to switch before a certain time period has elapsed e.g. not moreoften than L1 measurement period, such as 200 ms. The UE may also berestricted to not switch between different RSRQ measurement methodsbefore completing the L1 filtering (and/or L3 filtering of the ongoingmeasurement). The UE may also be restricted to not switch betweendifferent RSRQ measurement methods before completing the evaluation ofthe ongoing event or event reporting. When measuring relative RSRQ,which is used to compare RSRQ from different cells such as serving andneighbor cells' RSRQ, the UE may decide to use only one of the methodse.g. first method or second method.

FIG. 5 shows a flow chart over the device embodiment A.

(100) The device receives measurement configuration from the NW node.The configuration may include which quantity to measure (e.g. RSRQ)together with frequency layers and filter constants to use to determinethe final measurement result.

(110) The device determines the cell synchronization status (timesynchronization metric) and/or the cell load status (experienced cellload) according to described above.

(120) Based on determined information in (110) the device determines(mobility management) measurement method used for the configuredmeasurement quantity.

(130) Measurement is made according to configured information.

(140) Measurement results are reported (e.g. mobility managementmeasurement report) to NW node either on event basis or on regularbasis.

UE Based Decision for Switch of Measurement Method Including Signalingto NW node (B)

This embodiment is an extension of the above mentioned method. In thiscase the UE autonomously selects first or second type of RSRQ but in themeasurement report it indicates which definition was used or anyinformation pertaining to the measurement method used for RSRQmeasurement (e.g. 0=old i.e. first method and 1=new i.e. second method).In some embodiments, same RSRQ measurement for all detected cells areused, only 0 or 1 is transmitted, however in embodiments where differentcell RSRQ are estimated using different methods, there is a “1” or “0”transmitted for respective cell in the measurement report. If differentmethods are used for relative RSRQ from different cells (e.g. servingand neighbor cells) then UE indicates which method is used for each ofthe two RSRQ in the measurement report.

According to another aspect of this embodiment the NW node may alsoconfigure the UE that whether the UE should include the informationabout the measurement method used for measuring RSRQ or not.

FIG. 6 shows a flow chart over device embodiment B. The first four stepsof FIG. 6 are the same as (or very similar to) the steps described inconnection with FIG. 5 and are therefore denoted with the same referencenumbers.

(100) The device receives measurement configuration (measurementconfiguration message) from the NW node. The configuration may includewhich quantity to measure (e.g. RSRQ) together with frequency layers andfilter constants to use to determine the final measurement result.

(110) The device determines the cell synchronization status and/or thecell load status according to described above.

(120) Based on determined information in (110) the device determinemeasurement method used for the configured measurement quantity.

(130) Measurement is made according to configured information.

(250) Measurement method and measurement results for respective cells inthe measurement set are reported to NW node either on event basis or onregular basis.

NW node (C)

This is a group of embodiments that may, for example, be a correspondingNW node embodiment to the device embodiment (B). The NW node typicallyreceives measurement reports from the device either on regular basis(every 500-1000 ms, say) or on event basis or on event triggeredperiodic manner (when a device triggers a handover event according towell-known prior art principles). In the measurement report, not onlythe RSRQ measurement on respective cell in the measurement set istransmitted according to some embodiments but also which RSRQ methodthat has been used for respective cell. The NW node then takes thisinformation into account and may apply compensation (e.g.adding/subtracting a constant/bias or scaling the result) to at leastsome of the received measurements in order to determine an adjusted RSRQmeasurement that is used in the further RRM (e.g. for HO decisionsetc.). The compensation may be done based on NW node knowledge of radiocharacteristics which for example may comprise of one or more of cellsynchronization status (asynched/synched NW, time synchronizationmetric) or (experienced) cell load in serving cell and/or neighboringcells. In one example embodiment the NW node does the determinationautonomously, while in another embodiment the NW node communicates withother NW nodes over (for instance) the X2 interface in order todetermine whether compensation of RSRQ measurements are needed or not.For example the NW acquires cell load information about neighboringcells by means of measurements received from other nodes. Examples ofmeasurements are base station mean or maximum transmit power, overloadindicator, network load indicator, mean or maximum cell transmissionrate (e.g. bit rate, throughput etc), mean or maximum transmit power ofdata channels (e.g. PDSCH), control channels (e.g. PDCCH etc) etc. Thenetwork node may also determine the sync level of cells based on UEmeasurements like reference signal time difference (RSTD) measurementdefined in the LTE standard. The RSTD is measured by the UE on referencesignals received from two cells: reference cell and neighbor cells.

Again, the compensation may be made on a subset of all RSRQ measurements(e.g. a subset of cells). The amount of compensation to be applied canbe based on a pre-defined or lookup table which maps cell load (e.g.x^(th) percentage of total load), synchronization status of thecells/network (e.g. sync or async) and the amount of compensation (e.g.y dB). The lookup table may also be obtained under different radioenvironment which may comprise of one or more of UE speed, multipathdelay profile, delay spread etc. The compensation may vary between −10to +10 dB depending upon the scenario. These lookup tables can beobtained based on field tests, survey or historical data.

FIG. 7 shows a flow chart over the NW node embodiment C.

(300) The NW node configures measurement quantity to measure and reportto the camping/connected devices (measurement configuration message).

(310) The NW node receives measurement reports (mobility managementmeasurement reports) from the respective devices, together with usedmeasurement method used for respective cell in the device measurementset.

(315) Optionally the NW node receives cell load information (experiencedcell load) and timing information (time synchronization metric) fromneighboring cell over (for instance) the X2 interface.

(320) NW node may instead of (315) determine NW sync status (timesynchronization metric) and/or cell load (experienced cell load)autonomously.

(330) Based on information (315) and (320) the NW node determineswhether a subset of the measurement reports need to be compensatedaccording to described above, in order to determine a modifiedmeasurement report.

(340) The NW node then uses the modified measurement reports in mobilitymanagement procedures, e.g. in the further RRM processing and decisions(HO for instance).

NW Configurable Switching of Measurement Method (D)

In this embodiment, the NW node configures the device with which RSRQmeasurement method to use. For example the NW node may signal one bit (0or 1) to configure UE to use first method (e.g. 0) or second method(e.g. 1). The NW may also signal additional measurement parametersassociated with the RSRQ measurement for first and second methods i.e.parameter values may depend upon the method. Examples of measurementparameters are signal hysteresis, time to trigger, time hysteresis,layer 3 filtering coefficient etc. The configuration can be done duringinitial setup of a call or during a call or at the time of cell change(e.g. handover—HO). The configuration may be applicable to all cells inthe device measurement set, but may also be configured independently forrespective cell in the measurement set. For instance, the old RSRQmeasurement may be used for cells with low load or low signal quality,or neighboring cells (e.g. low C/I, SNR, SINR, CRS Es/Iot or PSS/SSSEs/Iot≦−3 dB, say) while the new may be used for high load cells orcells with high load or high signal quality (e.g. C/I, SNR, SINR, CRSEs/Iot or PSS/SSS Es/Iot>−3 dB, say) (serving cell and other strongneighboring cells).

So the UE is allowed to use old and new RSRQ measurement method butcontrolled by the network. The network configures UE whether to usefirst (old) or second (new) RSRQ. It may also be pre-defined that bydefault (i.e. if no indication is received from the NW node) the UE isrequired to use a specified method e.g. first method. The network mayalso use information related to radio characteristics such as cell load,synchronization status of the cells/NW, radio environment etc todetermine which measurement method is most suited for doing RSRQmeasurement. The NW node can determine these radio characteristics asdescribed herein.

FIG. 8 shows a flow chart over NW node embodiment D. The flow chartillustrates a method of a network node of a cellular communicationnetwork connectable to one or more wireless communication devices, themethod comprising (for each of one or more cells of the cellularcommunication network):

(400) optionally the NW node receives cell load information (experiencedcell load) from neighboring cells (acquiring an experienced cell load ofthe cell).

(410) optionally the NW node receive timing information (timesynchronization metric) for neighboring cells from devices (RSTDmeasurement for instance) (acquiring a time synchronization metricindicative of a time synchronization between the cell and one or moreother cells of the cellular communication network).

(420) the NW node determines the NW synchronization status (timesynchronization metric) and cell load (experienced cell load) for theserving (or optionally neighboring) cell(s).

(430) Based on information (400)-(420) the NW node configuresmeasurement method (via measurement configuration messages) to use forrespective device (transmitting a respective measurement configurationmessage to at least one of the wireless communication devices, whereineach measurement configuration message may comprise an instruction thatthe wireless communication device should use a particular mobilitymanagement measurement method, which may be selected from a group ofavailable mobility management measurement methods comprising a firstmobility management measurement method wherein measurements are madebased on a first number of symbols and a second mobility managementmeasurement method wherein measurements are made based on a secondnumber of symbols, and wherein the selection may be based on one or moreof the experienced cell load and the time synchronization metric).

(440) The NW node receives measurement reports (mobility managementmeasurement reports) from camping/connected devices (receiving one ormore mobility management measurement reports from respective ones of thewireless communication devices, wherein each mobility managementmeasurement report comprises an indication of a result of mobilitymanagement measurements performed by the respective wirelesscommunication device).

(450) Received measurement reports are used in mobility managementprocedures, e.g. in further RRM processing/handling/decision (using theresult of mobility management measurements in a mobility managementprocedure).

Application to SON/MDT (E, NW node) (F, Device)

This embodiment may be applicable for SON (Self Organized Network) orMDT (Minimization of Drive Test) i.e. used for network planning Thesefeatures especially MDT is used by the NW node to configure the UE tolog and store measurements performed on cells. The UE then reports thelogged measurements along with timestamp and location when measurementwas done to the NW node. The NW node uses the received results forstatistical purposes, for example, one or more tasks related to thenetwork planning e g tuning of or setting up of cell parameters such astransmit power, cell BW, number of antennas etc. The device isconfigured (e.g. by measurement configuration messages) by the networkto log RSRQ using both old and new RSRQ measurement method and log e.g.their difference in log scale/ratio in linear scale/mismatch between twovalues, either as a background measurement in idle mode or other lowactivity state like CELL_PCH or URA_PCH in HSPA (every time the devicewakes up from DRX) or in connected mode in LTE (RRC_connected) orCELL_DCH state in HSPA. This requires the UE to perform the RSRQ fromthe same cell using both first measurement method and second measurementmethod. The UE may perform first and second RSRQ at the same time or atdifferent times or at partially overlapping time.

The UE reports (e.g. in mobility management measurement reports) themeasurement data to the network node which then uses it for networkplanning, gathering statistics for coverage, current cell load etc. inthis embodiment, the device may report both RSRQ, or a differencebetween the RSRQ of serving/camping cell and detected neighboring cells.

The NW node based on the results may also decide whether to configurethe UE with the first measurement method or with the second measurementmethod i.e. method in embodiment in section 6.4 may take into accountthese results. For example the network node may configure the UE to useonly first method in certain location or for measuring on certain cellscase provided the mismatch between first and second RSRQ (as indicatedby reports) is larger than the threshold e.g. larger than 3 dB.

The measurement reports may be transmitted on regular basis or on eventbasis, for instance if the discrepancy between the measurements is abovea certain threshold (say more than 1 dB). The discrepancy may bemeasured and reported based on instantaneous measurements (one “snapshot”, or based on filtered measurements (i.e. average (weighted orequal weight of linear or logarithm of RSRQ)) over a certain timeconstant, configured by the NW node or defined in the standard.

FIG. 9 shows a flow chart over a NW node embodiment (E)

(500) The NW node configures (a subset of) connected/camping devices formultiple measurement methods for determination of a certain measurementquantity (e.g. RSRQ).

(510) The NW node receives measurement reports for (the subset of)connected/camping configured as in (510).

(520) Received measurement reports are used in further RRMprocessing/handling/decision/NW planning/statistical purposes, etc.

FIG. 10 shows corresponding device embodiment (F)

(600) The device receives SON/MDT measurement configuration from theserving/camping NW node.

(610) The device does measurement using both first and secondmeasurement method according to received configuration information

(615) optionally the device determines whether an event is triggered.The event may be that the discrepancy between the result for the firstand second measurement method differs more than a first threshold, asdescribed above.

(620) A Measurement report is transmitted to NW node includinginformation associated with both measurement methods (this may betriggered by an event (615), or transmitted on regular basis).

In the above description we have exemplified with measuring a certainsignal quality using two different method, each uses different receivedsignals for the determination, but the invention also covers the casewith three or more measurement methods.

FIG. 10 may also be used to illustrate a method of a wirelesscommunication device connectable to a cellular communication network,which may be applied in association with the method of the network nodeas illustrated in FIG. 8.

In this case, the method of FIG. 10 may be understood to comprise (foreach of one or more cells of the cellular communication network):

(600) receiving a measurement configuration message from a network nodeof the cellular communication network, wherein the measurementconfiguration message comprises an instruction that the wirelesscommunication device should use a particular mobility managementmeasurement method, the particular mobility management measurementmethod selected from a group of available mobility managementmeasurement methods comprising a first mobility management measurementmethod wherein measurements are made based on a first number of symbolsand a second mobility management measurement method wherein measurementsare made based on a second number of symbols (compare with (430) of FIG.8)

(610) performing mobility management measurements according to theparticular mobility management measurement method.

(620) transmitting a mobility management measurement report to thenetwork node of the cellular communication network comprising anindication of a result of the performed mobility management measurements(compare with (440) of FIG. 10).

Method in UE of Signaling Capability of Switching RSRQ MeasurementMethods

According to this embodiment the UE which is capable of switchingbetween first and second measurement methods for measuring RSRQ (e.g. asdescribed earlier herein) may also inform the network node that itsupports such capability (capability indication message). The UE mayreport the capability to NW via RRC signaling (e.g. to eNB, RNC, BSCetc). The UE may also signal the capability to positioning node (e.g.E-SMLC) via LTE positioning protocol (LPP). The UE may also includeadditional information in the capability indication message which maycomprise of one or more of the following:

-   -   UE is capable of only autonomously switching between the first        and second measurement methods.    -   UE is capable of autonomously switching between the first and        second measurement methods as well as informing which method is        used for measuring RSRQ.    -   UE is capable of receiving configuration and using it for using        first or second method for RSRQ measurements.    -   UE is capable of performing RSRQ using any of the above        principles for cells on any one or more of serving carrier, for        inter-frequency carrier, inter-RAT carrier, multicarrier/CA,        CoMP, positioning etc.    -   HD-FDD capable UE is also capable of adjusting its positioning        measurement procedure e.g. according to principles explained        herein.

The acquired capability information may be used by the receiving networknode and/or positioning node for taking one or more radio operationtasks or radio resource management actions. Examples of radio operationtasks are decision whether to configure the UE with the firstmeasurement method or with the second measurement method, whether toapply the compensation to account for the mismatch between first andsecond type of measurement etc.

The UE may send the capability information to the network node and/orpositioning node in any of the following manner:

-   -   Proactive reporting without receiving any explicit request from        the network node (e.g. serving or any target network node)    -   Reporting upon receiving any explicit request from the network        node (e.g. serving or any target network node)    -   The explicit request can be sent to the UE by the network        anytime or at any specific occasion. For example the request for        the capability reporting can be sent to the UE during initial        setup or after a cell change (e.g. handover, RRC connection        re-establishment, RRC connection release with redirection, PCell        change in carrier aggregation (CA), primary component carrier        (PCC) change in PCC etc).

In case of proactive reporting the UE may report its capability duringone or more of the following occasions:

-   -   During initial setup or call setup e.g. when establishing the        RRC connection    -   During cell change e.g. handover, primary carrier change in        multi-carrier operation, PCell change in multi-carrier        operation, RRC re-establishment, RRC connection release with        redirection etc.

Example Advantages of Some Embodiments

-   -   Reported RSRQ reflects true and consistent quality of a cell        even though radio characteristics may vary over time.    -   The UE implementation and network implementation have more        freedom to choose the most suitable method.    -   The UE and NW can optimize and use the most appropriate RSRQ        depending upon radio characteristics/scenarios.

FIG. 11 is a combined flow chart and signaling diagram illustrating someembodiments of the invention.

A UE may transmit its capability (731 Capab) to a NW node in step 701and the capability may be received by the NW node in step 711 (comparee.g. with “Method in UE of signaling capability of switching RSRQmeasurement methods” above).

The NW node may transmit a configuration (732 Config) of mobilitymanagement measurement method to the UE in step 712 and theconfiguration may be received by the UE in step 702 (compare e.g. withsteps 430 and 600).

Optionally, the NW node may transmit load and/or sync information (733Info) to the UE in step 713 and the information may be received(acquired) by the UE in step 703. These steps are particularlyapplicable in the context of FIGS. 5 and 6 where the UE selects mobilitymanagement measurement method, which selection is illustrated in step704. These steps may be omitted if the NW node selects mobilitymanagement measurement method and the configuration (732 Config) ofmobility management measurement method specifies which method to use.

In step 705, the UE performs the measurements according to the selectedmobility management measurement method (compare e.g. with step 610).

The result of the measurements may be reported (737 Report) by the UE tothe NW node in step 707 and the report may be received by the NW node instep 717 (compare e.g. with steps 620 and 440).

Optionally, the UE may also transmit load and/or sync information (738Info) to the NW node in step 708 and the information may be received bythe NW node in step 718. In some embodiments, step 718 (load and/or syncacquired from UE or from another source) may be performed before step711. Then, the NW node may select mobility management measurement methodbased on the information and the configuration (732 Config) of mobilitymanagement measurement method specifies which method to use.

Compensation of measurements (e.g. based on the information of step 718)may be performed in step 719.

The measurements may be used for mobility management as illustrated instep 720 for handover (compare e.g. with step 450) and in step 706 forcell re-selection, and/or as statistics (e.g. for SON) as illustrated instep 721.

FIG. 12 is a schematic block diagram illustrating an arrangement for awireless communication device (UE) 900 connectable to a cellularcommunication network according to some embodiments. The arrangementmay, for example, be adapted to perform any of the methods as describedin connection with FIGS. 5, 6, 10 and 11 (UE part).

The arrangement comprises a mobility management measurement unit (MMMEAS) 920, a transmitter and a receiver (transceiver TX/RX) 910.

The mobility management measurement unit may be adapted to performmobility management measurements according to a selected method, and thetransceiver may be adapted to transmit and receive various signals,messages, etc. as described above.

The arrangement may also comprise a selector (SEL) 960, a selection unit(CELL SEL) 930 and at least one of a cell load acquiring unit (LOAD) 940and a time synchronization metric acquiring unit (SYNC) 950.

The cell load acquiring unit may be adapted to acquiring an experiencedcell load of the cell, the time synchronization metric acquiring unitmay be adapted to acquire a time synchronization metric indicative of atime synchronization between the cell and one or more other cells of thecellular communication network, and the selector may be adapted toselect a mobility management measurement method based on at least one ofthe experienced cell load and the time synchronization metric.

The selection unit may be adapted to perform a cell reselectionprocedure based on the mobility management measurements.

In some embodiments:

-   -   the receiver is adapted to receive a measurement configuration        message from a network node of the cellular communication        network, wherein the measurement configuration message comprises        an instruction that the wireless communication device should use        a particular mobility management measurement method, the        particular mobility management measurement method selected from        a group of available mobility management measurement methods        comprising a first mobility management measurement method        wherein measurements are made based on a first number of symbols        and a second mobility management measurement method wherein        measurements are made based on a second number of symbols,    -   the mobility management measurement unit is adapted to perform        mobility management measurements according to the particular        mobility management measurement method, and    -   the transmitter is adapted to transmit a mobility management        measurement report to the network node of the cellular        communication network comprising an indication of a result of        the performed mobility management measurements.

FIG. 13 is a schematic block diagram illustrating an arrangement for anetwork node (NW NODE) 1000 of a cellular communication networkconnectable to one or more wireless communication devices according tosome embodiments. The arrangement may, for example, be adapted toperform any of the methods as described in connection with FIGS. 7, 8, 9and 11 (NW node part).

The arrangement comprises a receiver and a transmitter (transceiverTX/RX) 1010, and at least one of a cell load acquiring unit (LOAD) 1040and a time synchronization metric acquiring unit (SYNC) 1050.

The cell load acquiring unit may be adapted to acquire an experiencedcell load of the cell and the time synchronization metric acquiring unitmay be adapted to acquire a time synchronization metric indicative of atime synchronization between the cell and one or more other cells of thecellular communication network. The transceiver may be adapted totransmit and receive various signals, messages, etc. as described above

The arrangement may also comprise a compensator (COMP) 1060, which maybe adapted to compensate at least one measurement result indicationreceived by the transceiver based on at least one of the experiencedcell load and the time synchronization metric.

In some embodiments, the arrangement may further comprise a mobilitymanagement unit (MM) 1030 adapted to use a (possibly compensated)measurement result indication received by the transceiver in a mobilitymanagement procedure.

In some embodiments, the arrangement may further comprise a statisticalunit (STAT) 1020 adapted to use a (possibly compensated) measurementresult indication received by the transceiver for statistical purposes.

In some embodiments:

-   -   the cell load acquiring unit is adapted to acquiring an        experienced cell load of the cell,    -   the time synchronization metric acquiring unit is adapted to        acquire a time synchronization metric indicative of a time        synchronization between the cell and one or more other cells of        the cellular communication network,    -   transmitter is adapted to transmit a respective measurement        configuration message to at least one of the wireless        communication devices, wherein each measurement configuration        message comprises an instruction that the wireless communication        device should use a particular mobility management measurement        method, the particular mobility management measurement method        selected from a group of available mobility management        measurement methods comprising a first mobility management        measurement method wherein measurements are made based on a        first number of symbols and a second mobility management        measurement method wherein measurements are made based on a        second number of symbols, and    -   the receiver is adapted to receive one or more mobility        management measurement reports from respective ones of the        wireless communication devices, wherein each mobility management        measurement report comprises an indication of a result of        mobility management measurements performed by the respective        wireless communication device.

The described embodiments and their equivalents may be realized insoftware or hardware or a combination thereof. They may be performed bygeneral-purpose circuits associated with or integral to a communicationdevice, such as digital signal processors (DSP), central processingunits (CPU), co-processor units, field-programmable gate arrays (FPGA)or other programmable hardware, or by specialized circuits such as forexample application-specific integrated circuits (ASIC). All such formsare contemplated to be within the scope of this disclosure.

Embodiments may appear within an electronic apparatus (such as awireless communication device—e.g. a UE—or a network node—e.g. a NodeB)comprising circuitry/logic or performing methods according to any of theembodiments. The electronic apparatus may, for example, be a portable orhandheld mobile radio communication equipment, a mobile radio terminal,a mobile telephone, a base station, a base station controller, a pager,a communicator, an electronic organizer, a smartphone, a computer, anotebook, a USB-stick, a plug-in card, an embedded drive, or a mobilegaming device.

According to some embodiments, a computer program product comprises acomputer readable medium such as, for example, a diskette or a CD-ROM asexemplified by 800 in FIG. 14. The computer readable medium may havestored thereon a computer program comprising program instructions. Thecomputer program may be loadable into a data-processing unit (PROC) 830,which may, for example, be comprised in a mobile terminal or a networknode (810). When loaded into the data-processing unit, the computerprogram may be stored in a memory (MEM) 820 associated with or integralto the data-processing unit. According to some embodiments, the computerprogram may, when loaded into and run by the data-processing unit, causethe data-processing unit to execute method steps according to, forexample, any of the methods described herein.

FIG. 15 is a schematic block diagram illustrating an arrangement for awireless communication device or a network node according to someembodiments.

The example arrangement comprises a transceiver front-end (RX/TX FE), acontroller (CNTR), a radio frequency processing unit (RF PROC), abaseband processing unit (BB PROC) and a memory (MEM). The hardwareparts illustrated in FIG. 15 may be adapted to cooperate in implementingthe functional blocks presented in connection to FIGS. 12 and 13 in anysuitable manner.

Reference has been made herein to various embodiments. However, a personskilled in the art would recognize numerous variations to the describedembodiments that would still fall within the scope of the claims. Forexample, the method embodiments described herein describes examplemethods through method steps being performed in a certain order.However, it is recognized that these sequences of events may take placein another order without departing from the scope of the claims.Furthermore, some method steps may be performed in parallel even thoughthey have been described as being performed in sequence.

In the same manner, it should be noted that in the description ofembodiments, the partition of functional blocks into particular units isby no means limiting. Contrarily, these partitions are merely examples.Functional blocks described herein as one unit may be split into two ormore units. In the same manner, functional blocks that are describedherein as being implemented as two or more units may be implemented as asingle unit without departing from the scope of the claims.

Hence, it should be understood that the details of the describedembodiments are merely for illustrative purpose and by no meanslimiting.

The simulation results presented in FIGS. 1-4 will now be explained ingreater detail. FIGS. 1-4 illustrate RSRQ Link Simulation Results withRSSI Measurements in all Symbols.

A new definition of RSRQ where UE measures RSSI in all OFDM symbols in asubframe has been proposed in 3GPP standardization discussions, and away forward paper for doing link and system simulations to compare thedifference between existing and new RSRQ was approved in the 3GPPdocument R4-134475, “Way forward on RSRQ definition”, by Blackberry,Intel, Qualcomm, Verizon.

In FIGS. 1-4, link simulation results are provided to observe themismatch between the two different RSRQ definitions.

As for simulation assumptions with regard to FIGS. 1-4, the linksimulation parameters used for obtaining RSRQ results were based on theWF paper in R4-134475, “Way forward on RSRQ definition”. A summary ofparameters is also shown in table 1 below. The link simulation resultsare expressed in terms of CDF of mismatch between new RSRQ and old RSRQin dB. The results are shown for synchronous and asynchronous casesunder PDSCH loads of 25% and 100%.

The synchronous case is shown in FIGS. 1 and 2 for PDSCH load=100% and25% respectively. FIG. 1 shows mismatch between new RSRQ and old RSRQ insynchronized network with PDSCH=100% load and AWGN. FIG. 2 showsmismatch between new RSRQ and old RSRQ in synchronized network withPDSCH=25% load and AWGN.

It may be observed that under high PDSCH load (100%) the mismatchbetween new and old RSRQ is negligible. But under low load PDSCH load(25%) there is a bias. That is, the new RSRQ has a positive bias withrespect to the old RSRQ. However the bias is not so large given that theRSRQ measurement accuracy is within ±2.5 dB.

The asynchronous case is shown in FIGS. 3 and 4 for PDSCH load=100% and25% respectively. FIG. 3 shows mismatch between new RSRQ and old RSRQ inasynchronous network with PDSCH=100% load, AWGN and time offset between2 cells=randomly selected between 0 to 7 symbols. FIG. 4 shows mismatchbetween new RSRQ and old RSRQ in asynchronous network with PDSCH=25%load, AWGN and random offset between cell1 and cell2.

It may be observed that in asynchronous case under high PDSCH load(100%), the mismatch between new and old RSRQ is relatively small andwithin the RSRQ measurement tolerance/accuracy. But under low load PDSCHload (25%) there is a significant bias especially at SINR (i.e. Es/Iot)below 0 dB. In this case the new RSRQ has in particular more significantnegative bias with respect to old RSRQ at low SINR. The bias is welloutside the RSRQ measurement accuracy of ±2.5 dB.

TABLE 1 Link simulation parameters for RSRQ measurement resultsParameters Value Comments Measurement bandwidth 6 RBs System bandwidthof cells 6 RBs Number of cells 2 Cell1(measured); cell2 (neighbor)Synchronization level: 2 Synchronized cells Perfectly synchronized casesAsynchronous cells Time offset = random between 0-7 symbols PDSCHtransmission  25% In both cells probability: 2 cases 100% In both cellsControl channel space 3 OFDM symbols L1 measurement period 200 msMeasurement sampling 6 snaps shots over One snap shot = 2 ms long rate200 ms every 40 ms. L3 filtering disabled Transmit antenna 1 Receiveantennas 2 Receive diversity rule as defined in TS 36.214. Both antennaswith equal gain, no correlation between them. DRX OFF Propagationconditions AWGN Old RSRQ RSSI based on CRS RSSI is measured as inrelease 8 symbols New RSRQ RSSI based on all RSSI is measured in allOFDM symbols 0-7 symbols in a subframe

Thus, the mismatch very much depends upon the combination of load (PDSCHload) and level of network synchronization:

-   -   Under synchronous case the mismatch is very small especially        under high load.    -   Under asynchronous case the mismatch can be very substantial        under low load and moderate or low SINR.

1. A method of a network node of a cellular communication networkconnectable to one or more wireless communication devices, the methodcomprising, for each of one or more cells of the cellular communicationnetwork: transmitting a respective measurement configuration message,comprised in a radio resource control (RRC) configuration message, to atleast one of the wireless communication devices, wherein eachmeasurement configuration message comprises an instruction that thewireless communication device should use a particular signal qualitymeasurement method, the particular signal quality measurement methodbeing selected from a group of available signal quality measurementmethods comprising a first signal quality measurement method whereinmeasurements are made based on a first number of symbols and a secondsignal quality measurement method wherein measurements are made based ona second number of symbols; and receiving one or more signal qualitymeasurement reports from respective ones of the wireless communicationdevices, wherein each signal quality measurement report comprises anindication of a result of signal quality measurements performed by therespective wireless communication device. 2-3. (canceled)
 4. The methodof claim 1, further comprising: acquiring at least one of: anexperienced cell load of the cell; and a time synchronization metricindicative of a time synchronization between the cell and one or moreother cells of the cellular communication network.
 5. The method ofclaim 4 wherein the particular signal quality measurement method isselected based on one or more of the experienced cell load and the timesynchronization metric.
 6. The method of claim 1, wherein the signalquality measurement methods comprise methods to measure a receivedsignal strength indication (RSSI) and calculate a reference signalreceived quality (RSRQ) value based on the measured received signalstrength indication.
 7. The method of claim 1, wherein the particularsignal quality measurement method is to be performed by the respectivewireless communication device in one or more of the following states:Radio Resource Control (RRC) idle state; Radio Resource Controlconnected state; Idle mode; Universal terrestrial radio access networkRegistration Area Paging Channel (URA_PCH) state; Cell Paging Channel(CELL_PCH) state; Forward Access Channel (CELL_FACH) state; andDedicated Channel (CELL_DCH) state.
 8. The method of claim 1, furthercomprising using the result of signal quality measurements for one ormore of: a mobility management procedure; positioning of the wirelesscommunication device; a cell change; a handover; minimization of drivetests (MDT); network planning, configuration and tuning of radio networkparameters; self-organizing network (SON); network monitoring;interference management; determination and management of load; andinter-cell interference control.
 9. The method of claim 1, furthercomprising receiving a capability indication message from the wirelesscommunication device, wherein the capability indication message isindicative of a collection of signal quality measurement methodssupported by the wireless communication device, wherein the collectioncomprises at least the first and second signal quality measurementmethods.
 10. The method of claim 1, wherein the signal qualitymeasurements are mobility management measurements, the signal qualitymeasurement methods are mobility management measurement methods and thesignal quality measurement reports are mobility management measurementreports.
 11. A method of a wireless communication device connectable toa cellular communication network, the method comprising, for each of oneor more cells of the cellular communication network: receiving ameasurement configuration message, comprised in a Radio Resource Control(RRC) configuration message, from a network node of the cellularcommunication network, wherein the measurement configuration messagecomprises an instruction that the wireless communication device shoulduse a particular signal quality measurement method, the particularsignal quality measurement method selected from a group of availablesignal quality measurement methods comprising a first signal qualitymeasurement method wherein measurements are made based on a first numberof symbols and a second signal quality measurement method whereinmeasurements are made based on a second number of symbols; andperforming signal quality measurements according to the particularsignal quality measurement method.
 12. The method of claim 11 furthercomprising one or more of: transmitting a signal quality measurementreport to the network node of the cellular communication networkcomprising an indication of a result of the performed signal qualitymeasurements; using the performed signal quality measurements for cellselection; using the performed signal quality measurements for cellreselection; using the performed signal quality measurements for cellchange; using the performed signal quality measurements for positioning;storing or logging results of one or more of the performed signalquality measurements; using the performed signal quality measurementsfor Radio Resource Control (RRC) connection release with re-direction;and using the performed signal quality measurements for RRC connectionre-establishment. 13-14. (canceled)
 15. The method of claim 11, whereinthe signal quality measurement methods comprise methods to measure areceived signal strength indication (RSSI) and calculate a referencesignal received quality (RSRQ) value based on the measured receivedsignal strength indication.
 16. The method of claim 11, furthercomprising performing the particular signal quality measurement methodin one or more of the following states: Radio Resource Control (RRC)idle state; Radio Resource Control connected state; Idle mode; Universalterrestrial radio access network Registration Area Paging Channel(URA_PCH) state; Cell Paging Channel (CELL_PCH) state; Forward AccessChannel (CELL_FACH) state; and Dedicated Channel (CELL_DCH) state. 17.The method of claim 11, further comprising transmitting a capabilityindication message to the network node of the cellular communicationnetwork, wherein the capability indication message is indicative of acollection of signal quality measurement methods supported by thewireless communication device, wherein the collection comprises thefirst and second signal quality measurement methods.
 18. The method ofclaim 11, wherein the signal quality measurements are mobilitymanagement measurements, the signal quality measurement methods aremobility management measurement methods and the signal qualitymeasurement reports are mobility management measurement reports. 19-29.(canceled)
 30. A nontransitory computer readable medium, having thereona computer program comprising program instructions, the computer programbeing loadable into a data-processing unit and adapted to cause thedata-processing unit to execute a method when the computer program isrun by the data-processing unit wherein the method is of a network nodeof a cellular communication network connectable to one or more wirelesscommunication devices, the method comprising, for each of one or morecells of the cellular communication network: transmitting a respectivemeasurement configuration message, comprised in a radio resource control(RRC) configuration message, to at least one of the wirelesscommunication devices, wherein each measurement configuration messagecomprises an instruction that the wireless communication device shoulduse a particular signal quality measurement method, the particularsignal quality measurement method being selected from a group ofavailable signal quality measurement methods comprising a first signalquality measurement method wherein measurements are made based on afirst number of symbols and a second signal quality measurement methodwherein measurements are made based on a second number of symbols; andreceiving one or more signal quality measurement reports from respectiveones of the wireless communication devices, wherein each signal qualitymeasurement report comprises an indication of a result of signal qualitymeasurements performed by the respective wireless communication device.31. An arrangement of a network node of a cellular communication networkconnectable to one or more wireless communication devices, thearrangement comprising a receiver and a transmitter, wherein, for eachof one or more cells of the cellular communication network: thetransmitter is adapted to transmit a respective measurementconfiguration message, comprised in a Radio Resource Control (RRC)configuration message, to at least one of the wireless communicationdevices, wherein each measurement configuration message comprises aninstruction that the wireless communication device should use aparticular signal quality measurement method, the particular signalquality measurement method being selected from a group of availablesignal quality measurement methods comprising a first signal qualitymeasurement method wherein measurements are made based on a first numberof symbols and a second signal quality measurement method whereinmeasurements are made based on a second number of symbols; and thereceiver is adapted to receive one or more signal quality measurementreports from respective ones of the wireless communication devices,wherein each signal quality measurement report comprises an indicationof a result of signal quality measurements performed by the respectivewireless communication device.
 32. The arrangement of claim 31 whereinthe arrangement is a mobility management arrangement.
 33. A network nodefor a cellular communication network comprising the arrangement of claim31.
 34. An arrangement of a wireless communication device connectable toa cellular communication network, the arrangement comprising a signalquality measurement unit and a receiver, wherein, for each of one ormore cells of the cellular communication network: the receiver isadapted to receive a measurement configuration message, comprised in aRadio Resource Control (RRC) configuration message from a network nodeof the cellular communication network, wherein the measurementconfiguration message comprises an instruction that the wirelesscommunication device should use a particular signal quality measurementmethod, the particular signal quality measurement method selected from agroup of available signal quality measurement methods comprising a firstsignal quality measurement method wherein measurements are made based ona first number of symbols and a second signal quality measurement methodwherein measurements are made based on a second number of symbols; andthe signal quality measurement unit is adapted to perform signal qualitymeasurements according to the particular signal quality measurementmethod.
 35. (canceled)
 36. The arrangement of claim 34 wherein thesignal quality measurement unit is a mobility management unit, thesignal quality measurements are mobility management measurements and thesignal quality measurement methods are mobility management measurementmethods.
 37. A wireless communication device comprising the arrangementof claim
 34. 38. The method according to claim 1, wherein the first andsecond signal quality measurement method is for measuring receivedsignal strength indicator (RSSI) for reference signal received quality(RSRQ).
 39. The method of claim 11, wherein the first and second signalquality measurement method is for measuring received signal strengthindicator (RSSI) for reference signal received quality (RSRQ).
 40. Themethod of claim 34, wherein the first and second signal qualitymeasurement method is for measuring received signal strength indicator(RSSI) for reference signal received quality (RSRQ).